# Cognitive domain-specific impairments and associated risk factors in type 2 diabetes mellitus: a cross-sectional observational study based on neuropsychological assessment from Xiamen, China

## TL;DR

This study finds that type 2 diabetes patients in Xiamen, China, often experience cognitive impairments, especially in executive function, and identifies age and high lipoprotein(a) as risk factors.

## Contribution

The study provides new insights into cognitive impairments in T2DM patients from a subtropical Chinese region and identifies lipoprotein(a) as a novel risk factor.

## Key findings

- Executive function was the most commonly affected cognitive domain in T2DM patients with cognitive impairment.
- Older age and higher lipoprotein(a) levels were independently associated with cognitive impairment in T2DM patients.
- Routine cognitive screening is recommended for older T2DM patients and those with vascular risk factors.

## Abstract

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of cognitive impairment, yet limited research has been conducted in subtropical regions of China.

To examine the characteristics of cognitive impairment and identify the potential risk factors in patients with T2DM in Xiamen.

This cross-sectional observational study included 84 patients with T2DM from Zhongshan Hospital Xiamen University. Patients were grouped based on their Montreal Cognitive Assessment (MoCA) scores into a cognitively impaired group (T2DM-CI group, n = 52) and a cognitively normal group (T2DM-NCI group, n = 32). Multivariate logistic regression was used to identify independent risk factors.

Among the 52 patients in the T2DM-CI group, the most commonly affected cognitive domains were executive function (82.7%), language (75.0%), memory (61.5%), and attention (48.1%), with 59.6% exhibiting impairments in three or more domains. Compared with the T2DM-NCI group, the T2DM-CI group showed poorer performance in most MoCA subdomains—including visuospatial/executive function, language, delayed recall, abstraction, and orientation—as well as in individual cognitive domain tests (all P < 0.05), except for the Clock Drawing Test. Older age (OR = 1.167, 95% CI [1.045–1.303], P = 0.006) and higher lipoprotein (a) levels (OR = 1.109, 95% CI [1.020–1.205], P = 0.015) were independently associated with cognitive impairment in T2DM patients.

Cognitive impairment in T2DM affects multiple domains, with executive dysfunction most prominent. Age and elevated lipoprotein(a) may increase risk. Routine cognitive screening is warranted, particularly in older patients and those with vascular risk factors.